A gC1qR prevents white spot syndrome virus replication in the freshwater crayfish Pacifastacus leniusculus

The gC1qR/p32 protein is a multiple receptor for several proteins and pathogens. We cloned a gC1qR homologue in a crustacean, Pacifastacus leniusculus, and analyzed the expression of P. leniusculus C1qR (PlgC1qR) in various tissues. The gC1qR/p32 transcript was significantly enhanced by white spot syndrome virus (WSSV) infection 6 h after viral infection both in vitro in a hematopoietic tissue cell culture (Hpt) and in vivo compared to appropriate controls. Moreover, PlgC1qR silencing in both the Hpt cell culture and live crayfish enhanced the WSSV replication. In addition, by making a recombinant PlgC1qR protein we could show that if this recombinant protein was injected in a crayfish, Pacifastacus leniusculus, followed by injection of WSSV, this significantly reduced viral replication in vivo. Furthermore, if the recombinant PlgC1qR was incubated with Hpt cells and then WSSV was added, this also reduced viral replication. These experiments clearly demonstrate that recombinant PlgC1qR reduce WSSV replication both in vivo and in vitro. The results from a far-Western overlay and glutathione S-transferase pull-down assays showed that PlgC1qR could bind to VP15, VP26, and VP28. Altogether, these results demonstrate a role for PlgC1qR in antiviral activity against WSSV.